Question

The following data on x = score on a measure of test anxiety and y = exam score for a sample of n = 9 students are consistent with summary quantities given in a paper. Higher values for x indicate higher levels of anxiety. Compute the value of the correlation coefficient. (Give the answer to four decimal places.)
r =

x	23	14	14	0	16	19	19	15	20
y	43	60	49	78	50	51	45	51	52

Answer 1

Solution:

X	Y	XY	X^2	Y^2
23	43	989	529	1849
14	60	840	196	3600
14	49	686	196	2401
0	78	0	0	6084
16	50	800	256	2500
19	51	969	361	2601
19	45	855	361	2025
15	51	765	225	2601
20	52	1040	400	2704

n	9
sum(XY)	6944.00
sum(X)	140.00
sum(Y)	479.00
sum(X^2)	2524.00
sum(Y^2)	26365.00
Numerator	-4564.00
Denominator	4943.88
r	-0.9232

Compute the value of the correlation coefficient:

r = -0.9232